Chapter 15 – Environmental Hazards and Human Health

27/10/2010 01:06

1. Differentiate between a hazard and a risk. Where does
vulenrability fit in?

In terms of environmental health a hazard is anything that can cause (1) injury, disease, or death to
humans; (2) damage to personal or public property; (3) deterioration or
destruction of environmental components. Hazard has a risk. Risk is the probability of suffering
injury, disease, death or some other loss as a result of exposure to a hazard.

The existence of a hazard alone does not mean that
undesirable consequences will follow. Risk=Hazard×Vulnerability; Vulnerability to risks: some people are
more vulnerable to certain risks than others.

2. Define morbidity, mortality and epidemiology.

Morbidity is the incidence of disease in a population and
is commonly used to trace the presence of a particular type of illness
(influenza, diarrheal disease etc.). Mortality is the incidence of death in a
population. Epidemiology is the study of the presence, distribution and
prevention of disease in populations.

3. Describe public-health roles of the CDC and the WHO.

CDC is the Centers of Disease Control and Prevention
leading federal agency of public health and safety in U.S. The CDC’s mission is
“to promote health and quality of life by preventing and controlling disease,
injury, and disability”; public health as prevented and controlled disease,
injury, and disability. WHO United Nations agency with the mission of enabling
“all peoples to attain the highest possible level of health”; public health as
the highest possible level of health.

4. What are the four categories of human environmental
hazards? Give examples of each.

Cultural: mortality and disability as a matter of choice or
at least could be influenced by choice. People engage in risky behavior and
subject themselves to hazards. Sunbathing, consuming alcoholic beverages.
Biological: the battle with pathogenic bacteria and viruses. The black plague,
malaria. Physical: natural disasters, including hurricanes, tornadoes, floods,
forest fires, earthquakes, land slides, and volcanic eruptions. 2004 Indian
Ocean tsunami, 2005 August hurricane Katrina in U.S. Chemical: exposure to
chemicals such as cleaning agents, pesticides, fuels, paints, medicines, etc.
Toxicity depends on dose. Heavy metals as carcinogens.

5. List as many you can of the top 10 risk factors that are
responsible for global mortality and disease.

7. What is the significance of malaria worldwide, and what
are some recent developments in the battle against this disease?

Of the infectious diseases present in the tropics, malaria
is by far the most serious, accounting for an estimated 350-500 million cases
each year and more than million deaths. Eradication of the anopheles mosquito
by using insecticides; Chloroquine drug, artemisinin drug; providing
insecticide-treated nets over beds in threat areas; sequence of genomes of
Anopheles mosquito and P. flaciparum (most lethal malaria parasite) to target
potential weak points in both organisms in the search for new vaccines and
drugs.

8. Outline the four steps of risk assessment used by EPA.

Hazard assessment: the process of examining evidence
linking a potential hazard to its harmful effects. Dose-response assessment:
analyzing the relationship between the concentrations of chemicals in the dose
and both the incidence and the severity of the response. Exposure assessment:
identifying human groups already exposed to the chemical, learning how their
exposure came about, and calculating the doses and length of time of their
exposure. Risk characterization: pulling together all the information gathered
in the first three steps in order to determine the risk and its accompanying
uncertainties.

9. What methods are used to test chemicals for their
potential to cause cancer?

Examination of all the people exposed to the chemical;
animal testing; human subjects to test the product/chemical; the chemical or
process itself (determination of physical/chemical properties and what mode of
action might the chemical or process take in incl. cancer).

10. Describe the process of risk assessment for public
health as it was recently carried out by WHO. What is DAILY?

For assessment following risk factors were chosen for
special attention: potential global impact (the risk is likely to be among the
leading causes of poor health and of mortality); high likelihood of causality
(it should be possible to trace cause-effect relationships between poor health
and the factor in question); modifiability (it should be possible to develop
countrywide risk reduction policies); availability of data (there must be
reliable data on the prevalence of the risk factor and its relationship to
disease and mortality); the data collected must be assessed with the use of a
“common currency”, one that facilitates a comparison of different types of
risks. DAILY: the “disability-adjusted life year”, one DAILY represents the
loss of one healthy year of a persons life; a measurement used by WHO for risk
assessment.

11. Discuss the relationship between public risk perception
and assessment, on the one hand, and public policy on the other.

Public risk perceptions – peoples intuitive judgments about
risk, these are not consistent with the results of coming from a scientific
analysis of risk (e.g. risk assessment). The public perception of risks is
often more a matter of outrage than hazard. Hazard expresses primarily a
concern for fatalities only, outrage expresses a list of additional concerns
(lack of familiarity with a technology, risk is voluntary, public impression of
hazards, overselling safety, mortality, control, fairness). Moreover public
perception of risk is strongly influenced by the media. Public concern drives
public policy, as a result some serious risks may get less attention than they
deserve.

12. What is the precautionary principle, and how would
employing the principle better our approach to environmental public policy?

As the use of risk assessment has come under attack in
recent years the precautionary principle was established. The concerns about
risk assessment are: (1)it does not adequately reflect the uncertainty inherent
in much of the assessment process; (2) it has been largely employed in
situations where a chemical or a process is already in use; and (3) the burden
of proof of harm falls largely on the regulators. Therefore precautionary
measures should be taken where an activity raises threats of harm to human health
or the environment, even if some cause-and-effect relationships are not fully
established scientifically. In other words the proponent of an activity, rather
than the public,should bear the burden of proof.